<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>OOP JS</title>

</head>
<body>
<p id="demo">test</p>
<script>
    alert("start!");
    function printMsg() {
        var person = {userName: "Jack", userAge: 13};
        document.getElementById("demo").innerHTML = person.userName + "\t age:" + person.userAge;
    }
    printMsg();
</script>

</body>
</html>